C03E.pdf

May.17,2013

• This catalog has only typical specifications. Therefore, please approve our product specifications or transact the approval sheet for product specifications before ordering.

47

Continued on the following page.

Continued from the preceding page.

4. Type of Applied Voltage and Self-heating Temperature

1. Confirm the operating conditions to make sure that no large

current is flowing into the capacitor due to the continuous

application of an AC voltage or pulse voltage.

When a DC rated voltage product is used in an AC voltage

circuit or a pulse voltage circuit, the AC current or pulse

current will flow into the capacitor; therefore check the

self-heating condition.

Please confirm the surface temperature of the capacitor so

that the temperature remains within the upper limits of the

operating temperature, including the rise in temperature due

to self-heating. When the capacitor is used with a

high-frequency voltage or pulse voltage, heat may be

generated by dielectric loss.

<Applicable to Rated Voltage of less than 100VDC>

1-1. The load should be contained to the level such that

when measuring at atmospheric temperature of 25°C,

the product's self-heating remains below 20°C and the

surface temperature of the capacitor in the actual circuit

remains within the maximum operating temperature.

<Applicable to Temperature Characteristic X7R, X7T

beyond Rated Voltage of 250VDC>

1-2. The load should be contained so that the self-heating of

the capacitor body remains below 20°C, when

measuring at an ambient temperature of 25°C. In

addition, use a K thermocouple of ø0.1mm with less

heat capacity when measuring, and measure in a

condition where there is no effect from the radiant heat

of other components or air flow caused by convection.

Excessive generation of heat may cause deterioration

of the characteristics and reliability of the capacitor.

(Absolutely do not perform measurements while the

cooling fan is operating, as an accurate measurement

may not be performed.)

<Applicable to Temperature Characteristic U2J beyond

Rated Voltage of 250VDC>

1-3. Since the self-heating is low in the low loss series, the

allowable power becomes extremely high compared to

the common X7R characteristics.

However, when a load with self-heating of 20°C is

applied at the rated voltage, the allowable power may

be exceeded. When the capacitor is used in a

high-frequency voltage circuit of 1kHz or more, the

frequency of the applied voltage should be less than

500kHz sine wave (less than 100kHz for a product with

rated voltage of DC3.15kV), to limit the voltage load so

that the load remains within the derating shown in the

following figure. In the case of non-sine wave,

high-frequency components exceeding the fundamental

frequency may be included. In such a case, please

contact Murata. The excessive generation of heat may

cause deterioration of the characteristics and reliability

of the capacitor.

(Absolutely do not perform measurements while the

cooling fan is operating, as an accurate measurement

may not be performed.)

1

10

100

0123456

Current (Ar.m.s.)

[Example of Temperature Rise (Heat Generation)

in Chip Monolithic Ceramic Capacitors in Contrast

to Ripple Current]

Sample: R characteristics 10μF, Rated voltage: DC10V

Ripple Current

100kHz

500kHz

1MHz

The temperature of the surface

of capacitor: 125°C or less (including self-heating)

U2J char., Rated Voltage: DC630V

Frequency [kHz]

1000

100

10

1

10

100

1000

1,000pF

to 680pF

2,200pF

4,700pF

10,000pF

22,000pF

47,000pF

Frequency [kHz]

U2J char., Rated Voltage: DC1kV

1000

100

10

1

10

100

10000

1000

1,000pF

to 470pF

10,000pF

4,700pF

2,200pF

Frequency [kHz]

1000

100

10

1

10

100

(250)

1000

U2J char., Rated Voltage: DC250V

10,000pF

4,700pF

to 2,200pF

Sine-wave frequency VS allowable voltage

!Caution